Vehicular air bags have been recognized as one of the most effective means for ensuring the safety of passengers in automotive vehicles. The air bags are formed from a very strong synthetic material which is collapsed into a tightly folded condition and stored in the passenger compartment of the vehicle. The driver side air bag generally is disposed within the hub of the steering wheel, while passenger side front seat air bags are disposed in a special compartment of the dashboard. The air bags are operatively connected to sources of compressed air and to electronic sensors which rapidly direct a flow of air into the air bag in response to a sensed impact. The rapid movement of air into the air bag causes the air bag to quickly inflate to provide a cushion against which the vehicular occupant is urged in response to the impact of the collision. The air bag will then rapidly deflate.
The air bag of a vehicle is sewn together from a plurality of pieces of material such that in its inflated condition, the air bag will define an appropriate three-dimensional configuration for the particular shape of the passenger compartment. Since the size and shapes of vehicles vary considerably, the sizes and shapes of air bags also are subject to substantial variation. Air bags are seldom symmetrical, in view of the generally non-symmetrical configuration of the passenger compartment into which the air bags inflate. A typical air bag will comprise first and second side panels and a main body panel extending between and connecting the side panels along tightly sewn seams. In view of the irregular shape required for the inflated air bag, the seams may not be parallel nor of equal lengths.
The unusual three-dimensional configuration of vehicular air bags, and the considerable variation in shape for the air bags of different models of vehicles have resulted in air bags being manufactured in labor intensive manufacturing processes performed on conventional sewing machines. In particular, sewing machine operators merely take peripheral edge regions of pre-cut sections of an air bag and manually advance the peripheral edge regions through a conventional sewing machine. This process is extremely costly and time consuming. The cycle time for completing the sewing of an air bag generally is in the range of 15-30 minutes. The manufacturing problems will become even greater as more vehicles include air bags as standard equipment.
Sewing machines have been provided for varying degrees of automation. Prior art sewing machines include workpiece support tables that move a workpiece through a programmed pattern relative to a substantially fixed sewing head and bobbin head. Other automated sewing systems include an interconnected sewing head and bobbin head that move relative to a substantially fixed workpiece. Still other prior art sewing systems merely include two-dimensional templates to define a sewing path through which a workpiece is guided. Prior art sewing machines have further included workpiece feed means for linearly feeding the material to be sewn into and/or out of the sewing machine.
In view of the above, it is an object of the subject invention to provide a sewing system for automatically manufacturing vehicular air bags.
It is another object of the subject invention to provide a system that can readily be altered to manufacture air bags of different configurations.
It is a further object of the subject invention to provide a programmable sewing system that can readily accommodate the irregular three-dimensional configurations of a vehicular air bag and that can easily be converted to sew other irregular air bag configurations.
It is an additional object of the subject invention to provide a sewing system comprising a plurality of pairs of sewing and bobbin heads that are independently movable relative to one another through a plurality of different axes to sew irregular seams on a vehicular air bag.
Still an additional object of the subject invention is to provide a three-dimensional template which can undergo complex movements that are coordinated With the movement of a plurality of sewing machines.